<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>动画</title>
    <link type="text/css" href="style01.css" rel="stylesheet">
</head>
<body>
    <div>这是一个初始效果</div>
    <br/>
    <div class="div2">改变后的效果</div>
</body>
</html>